The underlying problem of the invention is to improve a coupled inductor having a core and two windings.
To this end, a coupled inductor having a core and two windings is provided, wherein the first winding has a first and second terminal end and wherein the second winding has a third and fourth terminal end, wherein the first to fourth terminal ends are arranged on a lower side of the core, wherein each winding has an intermediate section extending through a through-hole in the core, wherein the two windings are designed at least in the intermediate section as flat stripes each having first and second side faces with a large width and third and fourth side faces having a small width compared to the width of the first and second side faces, wherein the first side faces of both windings are arranged in the intermediate section perpendicular to the lower side of the core and wherein the two first side faces of the windings in the intermediate section face each other and/or abut each other in the intermediate section.
Surprisingly, arranging the first larger side faces of stripe-shaped windings in the intermediate section perpendicular to the lower side of the core significantly improves the electric and magnetic properties of the proposed coupled inductor. The placement of the stripe-shaped windings in the intermediate section in this fashion, i.e. with the narrow side faces directed upwards and downwards, respectively, and with the larger side faces to the left and to the right, respectively, helps the inductor to utilize almost its full volume of core material when operating. As a consequence, the size of the core and the coupled inductor can be made less than half than known coupled inductors.
According to an embodiment of the invention the core is divided in at least two parts being connected to each other.
This enables easy manufacture of the inventive coupled inductor. A distance between the two parts of the core can be precisely controlled by, e.g., putting a wire having a defined diameter or small glass balls with a defined diameter between the two parts of the core when connecting the two parts of the core. Connecting of the two parts of the core can, e.g., be achieved by gluing, e.g. by means of an epoxy resin.
According to an embodiment of the invention a parting plane between the two parts extends parallel to the lower side of the core. In this way easy manufacture of the inventive coupled inductor can be achieved.
According to an embodiment of the invention at least one of the parts of the core has a U-shape and defines a channel for accommodating the intermediate section of the two windings.
By providing a part of the core in a U-shape, the intermediate sections of the windings can be arranged in an easy and precise way, since the U-shaped part will provide for an exact location of the intermediate sections.
According to an embodiment of the invention a first part of the two parts of the core has the shape of a cuboid and a second one of the two parts of the core is U-shaped.
In this way, two simply shaped parts can form the core. The cuboid shaped part of the core can be easily attached to the U-shaped part, thereby fixing the intermediate section of the windings within the core.
According to an embodiment of the invention a parting plane between the two parts of the core extends from the lower to the upper side of the core and sections of the two windings are arranged between the two parts of the core.
Arranging the parting plane between the two parts of the core in this way makes assembly of the inventive coupled inductor even easier. The two parts of the core are brought together and the first winding and the second winding are arranged with their intermediate sections inbetween the two parts of the core.
According to an embodiment of the invention the through-hole in the core is formed by at least one groove being arranged in the side faces of the two parts of the core facing each other.
In this fashion, the through-hole is completed when the two parts of the core abut each other.
According to an embodiment of the invention the side face of each of the two parts of the core comprises a groove, the two grooves forming the through-hole. Each of the two parts of the core, therefore, has a groove which, in the assembled part of the core, forms part of the through-hole. Advantageously, the grooves are adapted to the size and shape of the intermediate sections of the windings. Thereby, the intermediate section of a winding can be placed within the groove and is thereby fixed in place. The two parts of the core with the winding already be placed in the groove can then be simply put together to complete the coupled inductor.
According to an embodiment of the invention the core has a front side and a back side, wherein the intermediate sections of the windings between the two parts of the core extend between the front side and the back side of the core and wherein the windings have sections being arranged parallel to the front side and the back side of the core.
In this way, the two windings can be easily fixed to the core and only little room is needed for the finished coupled inductor. The core may have grooves or recesses for accommodating the sections of the windings being arranged parallel to the front side and the back side of the core, respectively.
According to an embodiment of the invention the terminal ends are connected to the sections of the windings being arranged parallel to the front side and the back side of the core.
In this way, a very compact arrangement is achieved.
According to an embodiment of the invention the sections being arranged parallel to the front side and the back side of the core are arranged perpendicular to the intermediate sections and perpendicular to the parting plane.
According to an embodiment of the invention at least the first side faces of the windings in the intermediate sections between the two parts of the core are coated with an electrically isolating layer.
Further features and advantages of the invention follow from the claims, the drawings and the description as follows. Individual features of the different embodiments can be combined without departing from the scope of this invention.